System and method for food safety inspection

ABSTRACT

A system and a method for monitoring and inspecting food safety is disclosed. The system adopts insert and use concept that only requires an initial push on a button to begin its function. The system provides visual alert for different conditions if food products are in unsafe status. The system is pre-calibrated during manufacture without complicated or multi-step calibration or recalibration procedures during application. The system relies on modern surface-mount microprocessor technology that enables long-term calibration stability along with very low power consumption for extended battery life.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of, and claims priority to,U.S. patent application Ser. No. 13/184,656, filed on Jul. 18, 2011,which is a continuation of U.S. patent application Ser. No. 12/651,692,filed on January 4, 2010, now abandoned, which is a continuation of U.S.patent application Ser. No. 11/229,621, filed on Sep. 20, 2005, now U.S.Pat. No. 7,686,232. Each of the above-referenced applications is hereinincorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention generally relates to temperature measurement and,more particularly, to food safety inspection.

BACKGROUND OF THE INVENTION

In food service industry, during the course of transferring productsfrom either cold storage or normal cooking status to some designatedplace, food safety is a big concern. Regulatory authority and the foodservice industry have established that potentially hazardous foodproducts maintained either below 40 degree F. or above 140 degree F. aregenerally safe from the growth of potentially dangerous bacteria. Thus,the temperature window roughly between 40 degree F. and 140 degree F.can be considered to be a danger zone. To ensure food safety, a simpleand effective inspection method for monitoring food temperature and thenalerting if food temperature is in a danger zone is desired.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide aneasy-to-use food inspection device and method that ensures thatpotentially hazardous food products are in safe status.

Another object of the present invention is to provide a visual alert ifthe potentially hazardous food products are in unsafe status so thatpeople are warned in time to adopt necessary measures to ensure foodsafety.

In accordance with one aspect of this invention, a system and method ofinspecting potentially hazardous food products adopts a simple andstraightforward insert and use concept that only requires an initialpush on a button to begin its function.

In accordance with another aspect of this invention, a system and methodof inspecting potentially hazardous food products provides differentvisual alerts for different conditions if the potentially hazardous foodis in the danger zone.

In accordance with a further aspect of this invention, a system andmethod of inspecting potentially hazardous food products ispre-calibrated during manufacture using sensitive thermistor temperaturesensors and thus can eliminate or reduce complicated or multi-stepcalibration or recalibration procedures during application.

In accordance with a yet further aspect of this invention, a system andmethod of inspecting potentially hazardous products relies onmicroprocessor technology that enables long-term calibration stabilityalong with very low power consumption for extended battery life.

The above and other objects, features, and advantages of the presentinvention will be apparent in the following detailed description of thepreferred embodiments of the present invention when read in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of one embodiment of a food safety inspection deviceaccording to the invention.

FIGS. 2( a) and 2(b) are flowcharts illustrating a method for theoperation of the food safety inspection device according to anembodiment of the invention.

FIG. 3 is a diagram of another embodiment of the food safety inspectiondevice according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a diagram of one embodiment of a food safety inspection device100 for ensuring that the potentially hazardous food products (referredto “foods” thereafter) are in safe condition, i.e., the foodtemperatures are either below a lower temperature threshold (e.g., about40 degree F.) or above a higher temperature threshold (e.g., about 140degree F.), and providing a visual alert if the foods are in unsafestatus, i.e., the food temperatures fall between the lower temperaturethreshold (e.g., about 40 degree F.) and the higher temperaturethreshold (e.g., about 140 degree F.), according to the invention.

It should be understood that the range of 40 degree F. to 140 degree F.is exemplary only, and that the device can be configured to operateaccording to different ranges without departing from the spirit and thescope of the invention. For example, a range of 30 degree F. to 150degree F., or any other range suitable to the application, could beused.

The food safety inspection device 100 includes a power source 110, atemperature sensor 120, a reset mechanism 130, a warning mechanism (140,or 150, or 140 and 150), and a processor 160.

The food safety inspection device 100 is powered by a power source 110,which supplies power to electronic components of the device. The powersource can be either a DC or an AC power supply. The DC power supply canbe any suitable commercial batteries available on the market.

The temperature sensor 120 is used as a medium to physically touch theinspected food and thus sense the temperature of the food. Of course,the sensor could be applied to physically touch a container holding thefood (a plat, a can, et.) in addition to or instead of physicallytouching the food. According to one approach, the temperature sensorconsists of a sensor tip and a thermistor which is physically located inthe sensor tip's sheath; the sensing tip is about 6 inches in length andmade up of stainless steel. Any suitable device for sensing or measuringtemperature could be used.

The reset mechanism 130 is used to reset the device so that ameasurement can be initiated. According to one approach, the resetmechanism can be made as a pushable button. Any other suitable mechanismfor resetting the device could be used, such as toggle switch, etc.

The warning mechanism (140, or 150, or 140 and 150) is used to provide awarning when the inspected food is in unsafe status. The warningmechanism can be either in audio or visual form, or both. The audio formcan be any indicium which can give off an audio warning such as beeping.The visual form can be any visual indicium which can give off a visualwarning (e.g., flashing) such as light emitting diodes and light bulbs,or other suitable device for providing a visual indicia. According toone approach, the device has one visual indicium which can flash a colorwhen alerting. According to another approach, the device has two visualindicia, when alerting, one giving off a red flashing warning 140corresponding to one condition and the other giving off a blue flashingwarning 150 corresponding to another condition.

The processor 160 is used to process measured data corresponding to thetemperature of the inspected food. According to one approach, theprocessor 160 determines whether the food temperature falls below thelower temperature threshold or exceeds the higher temperature threshold,determines whether the food temperature falls between the lowertemperature threshold and the higher temperature threshold, determinewhether the food temperature falls between the lower temperaturethreshold and the middle temperature setpoint, and determine whether thefood temperature falls between the middle temperature setpoint and thehigher temperature threshold. Preferably, the processor comprises amemory, internal registers, a clock, and outputs. According to oneembodiment, ATTiny13 AVR microprocessor is adopted. Other types ofprocessors or controller-type devices could easily be used.

FIG. 2( a) is a flowchart illustrating the operation of a food safetyinspection device with an audio indicium or one visual indicium as itswarning mechanism according to one embodiment of the invention. FIG. 2(b) is a flowchart illustrating the operation of the food safetyinspection device with two visual indicia as its warning mechanismaccording to another embodiment of the invention. The method of FIGS. 2a and 2 b is described in connection with FIG. 1 in order to set forththe method in a concrete fashion easily understood by the person ofordinary skill. However, this articulation of the method is exemplaryonly, and the method could be implemented using structures differentfrom that of FIG. 1.

The user of the device first connects or installs a power source beforethe device is ready to inspect food as set forth in step 210. The userthen places the temperature sensor of the device on or into the food sothat the temperature sensor physically touches the inspected food as perstep 220. According to step 230, a reset mechanism is pushed to initiatethe device. According to one approach, if the device uses an audioindicium as its warning mechanism, the device then beeps to indicatethat the device is measuring the temperature of the inspected food.According to another approach, if the device uses one visual indicium(or two visual indicia) as its warning mechanism, the visual indicium(or indicia) light(s) up for several seconds (e.g., about 2 seconds).

According to one embodiment (i.e., the device uses audio indicium), whenthe monitored food is cold (e.g., below about 40 degree F.), such asmeat just taken out from a refrigerator, if the food safety inspectiondevice is applied, the audio indicium remains off, which means themonitored food is in safe status and no safety action needs to beundertaken, as per steps 240 and 250. When the monitored food is hot(e.g., above 140 degree F.), such as just-cooked soup, if the foodsafety inspection device is applied, the audio indicium remains off,which represents the monitored food is also in safe status and no safetyaction needs to be undertaken, as per steps 240 and 250.

Similarly, according to another embodiment (i.e., the device uses onevisual indicium [or two visual indicia]), when the monitored food iscold (e.g., below about 40 degree F.), if the food safety inspectiondevice is applied, the visual warning indicium (or indicia) remains off,as per steps 240 and 250. When the monitored food is hot (e.g., above140 degree F.), if the food safety inspection device is applied, thevisual warning indicium (indicia) remain off, as per steps 240 and 250.

When initially cold food is removed from cold storage and exposed to awarmer environment for certain period of time, e.g., a salad containeris taken out from a refrigerator and placed on a counter for laterserving, the temperature of the food gradually increases. Once thetemperature of the monitored food increases over a lower threshold(e.g., about 40 degree F.), the audio indicium or visual indicium (orindicia) gives off a warning. According to one approach (i.e., thedevice uses an audio indicium), the device starts to beep until thereset mechanism is pushed, which indicates that the monitored food is onunsafe condition, as per step 260. According to another approach (i.e.,the device has one visual indicium), the device starts to flash in afast blinking mode until the reset mechanism is pushed, as per step 260.According to one further approach (i.e., the device has two visualindicia), the red visual indicium starts to flash until the resetmechanism is pushed, as per steps 270 and 280.

Likewise, when initially hot food is exposed to air for a while, e.g., ajust-cooked soup, the temperature of the food gradually decreases. Oncethe temperature of the monitored food decreases below the highertemperature threshold (e.g., about 140 degree F.), the audio indicium orvisual indicium (or indicia) gives off warning. According to oneapproach (i.e., the device uses an audio indicium), the device starts tobeep until the reset mechanism is pushed, which indicates that themonitored food is on unsafe condition, as per step 260. According toanother approach (i.e., the device has one visual indicium), the devicestarts to flash until the reset mechanism is pushed, as per step 260.According to one further approach (i.e., the device has two visualindicia), the blue visual indicium starts to flash until the resetmechanism is pushed, as per steps 270 and 290.

If the temperature of the monitored food is around the middle oftemperature range between the lower temperature threshold (e.g., about40 degree F.) and the higher temperature threshold (e.g., about 140degree F.), according to one embodiment (i.e., the device uses twovisual indicia), the red indicium flashes when the monitored food isbelow a roughly middle temperature setpoint (e.g., about 90 degree F.)as per step 280, and the blue indicium will flash when the monitoredfood is above the roughly middle temperature setpoint (e.g. about 90degree F.) as per step 290.

The flash of the visual indicium can alert relevant personnel so thatsome action can be taken. For example, the temperature of the initiallyhot foods can be raised up above the higher temperature threshold (e.g.,about 140 degree F.), or the temperature of the initially cold foods canbe lowered down below the lower temperature threshold (e.g., about 40degree F.). Thus, the monitored foods can be monitored or returned to asafe condition. Of course, if the food is in unsafe status, theestablishment can simply dispose of the food rather than returning it toa safe temperature.

FIG. 3 illustrates how a food safety inspection device measures thetemperature of the inspected food according to an embodiment of theinvention.

To initiate a measurement cycle, the output ports 170 and 180 are firstdriven low for a time period proportional to a time constant, where thetime constant is the product of the thermistor 120 resistance, R, andcapacitor's 310 capacitance, C. This allows enough time for thecapacitor, C, to fully discharge. Then both output ports 170 and 180 aredriven high, charging the capacitor through the thermistor's resistance.Once the capacitor becomes adequately charged, the transistor 320 turnson and pulls the output port 180 low. The time for the output port 180to be driven from high to low by the transistor 250 is a function ofR.times.C.times.Constant of the Circuit. Since the resistance, R, of thethermistor is related to temperature of the sensor, the time lapse isdirectly related to the temperature. The processor's internal clock isused to measure this time lapse.

By means of a calibration procedure during manufacture, the time lapsesare calibrated to correspond to the designated temperatures, andprogrammed into the processor 160. By matching the measured time lapsewith the calibrated value stored in the processor 160, the processor 160can determine the actual temperature of the monitored food and thuswhether the food is in safe or unsafe status.

According to one embodiment, the processor can transmit the temperaturedata to a remote receiver at a designated interval to keep a record oftemperature history. The remote receiver could be any device which isable to receive, save, and display the transmitted data. The processorcould transmit the data through a wired connection (e.g., cables) orthrough a wireless connection (e.g., RF transmitter, etc.). The data canbe forwarded over a network (Internet, Intranet, etc.) to be monitoredand further evaluated.

One variation of the present invention is that the food safetyinspection device could be mounted on coolers. For example, when thecooler goes above 40 degree F., the device will flash a red light toalert people about the safety status of the foods in the cooler.Modification of the sensor 120 may be appropriate for this applicationso that the sensor can be easily attached to the inner wall of thecooler. The temperature sensor 120 can be detached from the othercomponents of the device so that the sensor is located inside the coolerand the other components of the device are attached or located outsidethe cooler.

One further variation of the present invention is that the device isredesigned so that it can float in a bath tub when a mother prepares forbathing a baby. If the bath water is too hot (i.e., above some specifictemperature), the device will flash and alert the mother so that themother can adjust the bath temperature to ensure the comfort and safetyof the baby. This embodiment could be implemented using the basiccomponents of FIG. 1, and with the addition of some protective materialto waterproof the device and provide for buoyancy.

A specific embodiment of the food safety inspection device according tothe invention has been described for the purpose of illustrating themanner in which the invention may be made and used. It should beunderstood that implementation of other variations and modifications ofthe invention in its various aspects will be apparent to those skilledin the art and that the invention is not limited by the specificembodiment described. It is therefore contemplated to cover by thepresent invention any and all modifications, variations, or equivalentsthat fall within the true spirit and scope of the basic underlyingprinciples disclosed and claimed herein.

1. A device for evaluating food safety, comprising: a processor forprocessing measured data corresponding to a food temperature, theprocessor programmed to determine whether the food temperature fallswithin a predefined safety zone or a predefined danger zone, saidpredefined danger zone being bound by a first temperature setpoint and asecond temperature setpoint wherein the first temperature setpoint islower than the second temperature setpoint, and said predefined safetyzone being temperature ranges outside said predefined danger zone; astorage device for storing measured data regarding food temperature; asensor for insertion or making physical contact with one or more fooditems and for outputting data corresponding to the food temperature; aone-touch switch for initiating measurement with a single push or othersingle movement of a finger; and an indicator for notifying a userwhether the food temperature is in said predefined danger zone or insaid predefined safety zone.
 2. The device of claim 1, wherein saidindicator is further configured to provide two visual indicia whichremain off when the food temperature is in said predefined safety zone,and wherein the two visual indicia provide a visual alert in differentcolors when the food temperature falls in said predefined danger zone,one color for when the food temperature is above the first temperaturesetpoint and below a third temperature setpoint, and the other color forwhen the food temperature is below the second temperature setpoint andabove the third temperature setpoint.
 3. The device of claim 2, whereinthe third temperature setpoint is between the first temperature setpointand the second temperature setpoint.
 4. The device of claim 1, whereinsaid indicator is further configured to provide one visual indiciumwhich remains off when the food temperature is in said predefined safetyzone, and wherein the visual indicium provides a visual alert when thefood temperature falls in said predefined danger zone.
 5. The device ofclaim 1, wherein said indicator is further configured to provide atleast one audio indicium to warn the user when the food temperaturefalls in said predefined danger zone.
 6. The device of claim 1, furthercomprising a sensing tip for providing a physical contact with the food.7. The device of claim 1, further comprising a switch for resetting saiddevice to start or restart operation.
 8. The device of claim 1, furthercomprising one or more batteries for supplying power to the device. 9.The device of claim 1, further comprising a remote receiver whichreceives, saves and/or displays the transmitted temperature data at adesignated interval.
 10. The device of claim 1, wherein the sensor iscalibrated during manufacture to establish a corresponding relationshipbetween the measured data and the food temperature.
 11. A method ofevaluating food safety, comprising: placing a sensor that is part of afood safety measurement device in physical contact with one or more fooditems; engaging a one-touch switch for initiating a measurement with asingle push or other discrete movement of a finger; measuring, using aprocessor, data corresponding to a temperature of the one or more fooditems via the sensor; and determining, by the processor, whether thefood temperature falls within a predefined safety zone or a predefineddanger zone, said predefined danger zone being bound by a firsttemperature setpoint and a second temperature setpoint wherein the firsttemperature setpoint is lower than the second temperature setpoint, andsaid predefined safety zone being temperature ranges outside saidpredefined danger zone; and alerting a user whether the food temperatureis in said predefined danger zone or in said predefined safety zone. 12.The method of claim 11, further comprising: resetting said device tostart or restart operation.
 13. The method of claim 11, furthercomprising: calibrating said device to establish correspondingrelationship between the measured data and the food temperature; andstoring said relationship in said device.
 14. The method of claim 11,further comprising: providing no visual alert when the food temperatureis in said predefined safety zone.
 15. The method of claim 11, furthercomprising: providing a visual alert when the food temperature falls insaid predefined danger zone.
 16. The method of claim 15, furthercomprising providing a first visual alert of one color when the foodtemperature is above the first temperature setpoint and below a thirdtemperature setpoint, the third temperature setpoint being between thefirst temperature setpoint and the second temperature setpoint; andproviding a second visual alert of another color when the foodtemperature is below the second temperature setpoint and above the thirdtemperature setpoint.
 17. The method of claim 11, further comprising:providing at least one audio indicium to warn the user when the foodtemperature falls in said predefined danger zone.
 18. The method ofclaim 11, further comprising: receiving, saving, and/or displaying themeasured temperature data at a designated interval via a remotereceiver.
 19. A device for monitoring safety of bathtub watertemperature, comprising: a sensor for making physical contact with waterin a bathtub and for outputting data corresponding to water temperature;a processor, coupled to said sensor, for processing measured datacorresponding to the water temperature, the processor programmed todetermine whether the food temperature falls within a predefined safetyzone or a predefined danger zone, said predefined safety zone beingbound by a first temperature setpoint and a second temperature setpointwherein the first temperature setpoint is lower than the secondtemperature setpoint, and said predefined danger zone being temperatureranges outside said predefined danger zone; a storage device for storingthe measured data regarding the water temperature; a one-touch switchfor initiating measurement with a single push or other single movementof a finger; and an indicator for notifying a user whether the watertemperature is in said predefined danger zone or in said predefinedsafety zone.
 20. The device of claim 19, being substantially enclosed ina waterproof housing and configured to float in water.